In my issued U.S. Pat. No. 4,572,101, an embodiment of a new and novel side-lifting tool for lifting wafer boats is disclosed. The side lifting tool of the '101 patent, in general, is adapted to engage a lifting rod or recess specially formed on the outside (i.e. non-wafer supporting) surface of the boat, so that the boat may be lifted prior to and after the supported wafers have received a high-temperature treatment which is disclosed in my '101 patent.
The figures in my '101 patent show that the side lifting tool has an essentially U-shaped handle, or lifting portion which terminates in a boat engaging portion that is adapted to engage exteriorly-located cross rods which are positioned on the side of a wafer boat, which boat is normally made of quartz glass and is termed a "quartz"boat. While the embodiment of my '101 patent has proven very useful and highly satisfactory, I have determined that a demand exists for a new and novel (a) side-lifting tool, (b) matching wafer boat, and (c) the combination thereof. My improved tool is durable and easy to use.
My newly-invented side lifting tool and matching boat is characterized by what is essentially a simple engaging/disengaging movement that may easily and readily be provided by a robotic end-effector system. In my earlier side lifting tool (of the '101 patent), a laterally and outwardly projecting portion of the tool had to be inserted at an angle approaching near vertical into a receiving location on the boat. Thereafter, a large relative rotational movement from vertical toward horizontal was required in order to couple the lifting tool to the boat.
My earlier tool was primarily intended for manual use, and the large rotational movement that was necessary to lockably engage boat to tool, and vice-versa, was easily supplied by an operator's hand and wrist. Such rotational movement under close and cramped conditions is not easily supplied. Additionally, a robotic system can readily provide the relatively limited rotational movements required for this invention.
The boats to be lifted are often located in cantilevered loading rods that are positioned at several elevations. Thus some loading rods are at waist level to a worker with additional higher and lower loading rods also positioned above and below that waist level loading station. Straight-handled lifting tools can easily reach and work with the waist-level loading locations, but do not work well for the high and/or lower loading locations. The present fulcrum and lifting part of the tool ( the "H" extensions) of the parent application is essentially mirror image in the upper and lower extensions from the point of attachment at the handle. Thus the tool can be turned over and used in either position equally as well for multi-level loading locations.
I have improved the tool further in this continuation-in-part application and make it more adaptable for use with boats positioned on multi-level loading locations by providing a deliberate bend (at an angle of about thirty degrees to the handle's axis) in the tool's handle.
Applicant calls the prior art in the '101 Patent to the attention of the Patent Office, but notes that such prior art is not as relevant as the '101 Patent itself.
The side lifting tool of this invention is characterized by a tool and matching boat which are especially adapted primarily for horizontal and limited vertical to horizontal ("angular") rotational movement in order to secure the tool to the boat for lifting purposes. The improved tool has an angled bend in the handle to improve its use and efficiency. In either the straight or angled-handled tools the engaging and lifting portions of the tool are essentially mirror images of each other relative to the point of attachment to the handle. This shape provides proper tool engagement and lifting whether it is right side up or turned over.